1. Field of the Invention
This invention relates to an impacting device for driving piles. More specifically, the invention pertains to a one cylinder diesel engine having a housing adapted to be seated upon a pile and a ram that reciprocates up and down within the housing, striking an anvil and driving the pile.
2. Description of the Prior Art
U.S. Pat. No. 3,437,157 discloses a diesel pile hammer that has a housing and a ram that moves up and down within the housing. The ram and the housing cooperate to define a power chamber and a separate scavenging chamber. These chambers are interconnected by a passageway with a reed valve therein that limits the flow of gases to the direction from the power chamber to the scavenging chamber. When starting the diesel pile hammer, it is necessary to raise the ram and drop it to obtain the necessary compression of a fuel-air mixture before combustion. A sub-atmospheric pressure is created in the scavenging chamber due to enlargement of the chamber by upward movement of the ram. This pressure makes it more difficult to lift the ram and also allows the reed valve to open. Some fresh air that is drawn into the power chamber by the ram's upward movement is allowed to escape into the scavenging chamber before compression and combustion of the initial starting charge.